Automatic tension device



Dec. 20, 1960 w. L. PERRY AUTOMATIC TENSION DEVICE 2 Sheets-Sheet 1Filed Nov. 25, 1957 W. L. PERRY AUTOMATIC TENSION DEVICE Dec. 20, 1960 2Sheets-Sheet 2 Filed Nov. 25, 1957 AUTOMATIC TENSION DEVICE Filed Nov.25, 1957, Ser. No. 698,439

Claims. (Cl. 242-150) This invention relates to an automatic tensiondevice in which the load which applies tension to the yarn is controlledby a yarn arm responsive to the yarn tension. It may be shown that insuch a device certain benefits are obtainable through use of a highmechanical advantage in controlling the load. The present inventionprovides a device in which these benefits, from high mechanicaladvantage, are obtainable over a wide range of differing enteringtensions, the device employing a large potential load which is largelybelieved in'an automatic manner, only that portion of the largepotential load which is unrelieved being employed to apply tension, andthis unrelieved portion being distributed to a considerable number ofmovable disks. In the opening of the successive disks by a knot, onlyapproximately that portion of each disks potential load which isunrelieved opposes the opening of the disk. The device is so constructedthat inertia effects opposing opening of the disks are reduced to aminimum.

' Other features of the invention involve a novel means of guiding theyarn through the tension device in proper relation to successive disks,and novel means for supporting the yarn against successive movable disksand for supporting the movable disks themselves.

Other advantages features of the invention will be apparent from thisspecification in which the invention is explained by a description of apreferred embodiment thereof.

In the accompanying drawings,

Fig. 1 is a plan view of the automatic tension device;

Fig. 2 is a fragmentary front elevation, partly in vertical section onthe line 22 of Fig. 1;

Fig. 3 is a rear elevation;

Fig. 4 is mainly in elevation as viewed from the line 4-4 of Fig. l, andpartly in vertical section taken through the axes of the third andfourth disks;

Fig. 5 is a detail, mainly in horizontal section on the axis of the yarnarm and weight lever;

Fig. 6 is a vertical section taken at the axis of one of the disks on alarger scale than preceding figures;

Fig. 7 is a vertical section taken on the line 77 of Fig. 6;

Fig. 8 is a vertical section similar to Fig. 6 showing a modified formof mounting for supporting an upper disk by a spring; and

Fig. 9 is a horizontal section taken on the line 9-9 of Fig. 8.

Before a description of the preferred construction of the tension deviceof this invention, there will be pointed out, in an approximate manner,certain factors and rela- 'tions involved in obtaining some of theobjects of this invention in its preferred construction.

In considering a tension device it is convenient to refer to acoefiicient C which represents the ratio between the increase in tensionadded to the yarn and the amount of loading force applied to the movabledisk (or disks) in adding this tension. Thus, if 2 grams force appliedto the disk increases the yarn tension by 1 grain the 2,965,332 PatentedDec. 20, 1960 coefiicient C would be 0.5. The coefiicient C is notsimply a coefiicient of friction, because this coefficient C allows forthe fact that not all the force applied to the disk is in turn appliedto the yarn. For instance the disk may be mounted in such manner and insuch relation to the yarn that only two-thirds of the loading force isapplied to the yarn. Nevertheless, the coefiicient C varies with thecharacter of the yarn and it is desirable to construct the device insuch manner that it will give nearly the same results even though thiscoefiicient varies considerably.

Any particular final or outgoing tension may be thought of, for purposesof approximate calculations, as consising of three parts.

The first part is the tension of the yarn entering the device and thismay be called the incoming tension.

The second part is what might be called an inherent minimum addition,tension which it is found will be added by the device even if the diskor disks are ineffective. This inherent minimum addition may beaccounted for largely by the fact that the yarn bends around the yarnarm and receives a snubbing tension therefrom. This inherent minimumaddition will vary and will of course be greater with rough yarn thanwith smooth yarn, and will be greater when operating at high tensionsthan when operating at low tensions. When operating in the region of 50g. this inherent minimum addition might for example be in the region of8 g.

The third part may be considered to be the tension applied by loading.

The tension applied by loading is under control of the final outgoingtension which acts upon the yarn arm. The device comes into equilibriumwith a final tension which balances these three parts.

The intended operation is to decrease the third part, the tensionapplied by loading, as the first part, incoming tension increases.However to do this the outgoing tension must increase and there willaccordingly always be some increase in outgoing tension as the incomingtension rises. It is desired to keep this increase in outgoing tensionwithin narrow limits.

Assuming that the load is to be applied by weight, it is useful todistinguish between such part of the load as may be relieved, and anypart which is not relievable and which may be called dead weight. Deadweight may represent weight of a disk or disks, connecting linkage andother parts which because of the construction of the device alwayscontribute to the pressure upon the yarn, and may vary considerably.

The mechanical advantage M with which the yarn arm acts to relieve theload has an influence upon the characteristics of the device and thereare advantages in making the mechanical advantage large. With increasingmechanical advantage M, the load is also increased.

The following Tables I and II, asume devices in which there is anappreciable but small amount of dead weight (50 g.), the device of TableI having a relatively low mechanical advantage M of 10 and the device ofTable II having a large mechanical advantage of 30.

It will be seen that Table II where the mechanical advantage is 30,shows a better regulation at the lower values of incoming tension thandoes Table I, where the mechanical advantage is 10. However for incomingtensions above 15.33, Table II shows no better regulation than Table I.Thus, the final tensions are the same in Tables I and II for an incomingtension of 20 g.

In Table II through this range of incoming tensions above 15.33 there isas great an increase in final tension as in incoming tension, resultingin exceeding the desired final tension when the incoming tension is ashigh as 20 grams. If a lower final tension than 50 grams were aimed for,and the total load available adjusted accordingly,

3 Table I there would be an even larger zone or range of incomingtensions'in which-the final tension would increase as much as did theincoming tension. The following Table III isbased upona desired'finaltension of 40 grams and an inherent minimum addition of 6.4 grams (onthe assumption that this latter will diminish proportionately with thedesiredfinal tension). It will be seen from this Table III that atincoming tensions above 6.93 g., an increasein incoming tension isreflected in 'an equal increase in final tension.

. Inherent minimu dition 6. 4 6. 4 6. 4 6. 4 6. 4 Tension desired to beaddedby load=(2) (3) (4) 31. 6 26. 67 26.6 23. 6 13. 6 6. Load re quiredfor desired tension= ()/(l) 63. 2 53.33 53. 2 47. 2 27. 2 7. Totalloadavailable. 1,200 1,200 1, 200 1,200 1,200 8. Dead Weight 50 50 50 50 509. Relievable load n 1, 150 1,150 1,150 1,150 1, 150 10. Loadcounterbalanced by final tension (See' 13 below) (13) XM '1, 140. 9 1,150 1,150 1,150 1,150 11. Net load applied 59.1 50 50 50 50 12. Tensionapplied byload- I ing 29. 55 25 25 25 25 13. Final) tension (3)+(4)+ Itmay be explained that in these tables, up to a point where all of therelievable load is relieved, the final'tension (item 13) is calculatedby the following equation, involving other items of the table:

(13): ni y+m M1 [M=l0. Dead weight=50 g.]

1, Cn'fifinient 0,5 2. Approximate desiredteir 5 i l m 50 1 3. Incomingtension 2 7 10 12 4. Inherent minimum'addition 8 8 8 8 8 5. Tensiondesired to be added by load=(2) (3)(4) 40 35 32 30 32 10 6. Loadrequired for 'desircd tension=(5)/(1) 80 70 64 50 44 7. Total loadavailable 500 500 500 500 500 8. Deadweight 50 50 50 50 50 9. Relievableload 450 450 450- 450 450 10. Load counterbalanced by final tension (See13-beloW)=(l-3) XM..-.L 433.3 441.6 446.6 450 450 15 11. Netioad'applicdfinn u. 66.7 58.4 53.4 50 50 12. Tension applied by loading33. 3 29. 2 26. 7 i 25 13. Final tension (3)+(4)+ 20 Table II '[M =30.Dead weight=50 g.]

1 Cneffinierit 0,5 2. Approximate desiredtension (grams) 50 3. Incomingtension 2 10 4. Inherent minimum 8 8 8 8 8 5. Tension 'desire'd e addedby load=(2). g (3)-(4).. 40 32 26.67 26 22 '6.-Load required r siredtension= (5)](1) 80 64 53. 33 52 I 44 7. 1, 500 1, 500 1, 500 1, 500"-8-. 50 50 50 50 9. Relievable load 1,450 1,450 1,450 1,450 1,450 10.Load counterbalanced by final tension (See 13 below) 13) M.- 1,425 1,4401,450 1,450 1,450 3 n. Netload 1ea.... 75 so so so 50 512.-l.ensionappied-byload- V ing 37.5 30 25 2s 25 13. Final tension(3)+(4)+- At and beyondv the vpoint where all relievable load is re.

It may further be explainedthat where, in these tables, the finaltension (item 13) is calculated to a fraction of a gram, the purpose ofcarrying the calculation to such a fine degree is not because ofanynecessary importance of the fraction of a gram in the final tension, butis "in order that theother:items. which afedcpndent upon item 13 will beapproximately consistent with the final tension as indicated by item 13."It 'will'be apparent that the calculations as to final tension shouldonly be regarded as approximate because they are based on an assumedcoefiicient'C and an approximate figure for the inherent minimumaddition of item 4.

Thus far only asinglecoefiicient C of 0.5 has been assumed. I-nactualpractice, this coefiicient will not remain constant but will -var y fordifferent yarns and may also vary somewhat for the same yarn. A lowercoefiicient will yield lower outgoing tensions and a higher coeiiicientwill yield higher outgoing tensions. It may be seen that when operatingin the region in which the relievable load is not totaly relieved, adevice having a large mechanical advantage is less sensitive to thesechanges in coefficient than is adevice having a small mechanicaladvantage.

The effect of a slightly increased coefficient'is shown in Tables Ia andIla where his assumed that in the de-. vices of Tablesl andll-thecoefiicient is -0.6 instead of 0.5.-

Tdble la.

[M=10. Dead weighte=50gtl l. Coefiicient" 0.6. 2. Approxi natetlshedten- W 'sio'n (are. as) 50 3. lnco'ni 1g ten ion..- -2- 7 10 12 204. lilie'e'it minimum addltion 8' 8' 8. 8. $3 5. Tensim dcsi'ed to beadded by load=(2) (3)(4).- 40 '35 32 30 22 6. Loading equired for de- Isi ed te nsi )n= (5)/(1) 66. 7 '58. 3 53. 3 50 36.7 7. Total loadavailable..." 500 500 500 500 500 8. Dead veiht 50 50 50 50 50 9.Relievable load "450 450 '450 450 450 10. Load c unterbalancedby-finaltensim(See13 below) (13) XM 442. 8 450 450 450 '450 g et loadapnlied 57. 2 50 50 50 13 24. 32 30 30 '30 30 44.28 45 48 50 58 TableIla [M =30. Dead weiglit=50 g.]

1. Coeiiicient 0.6 2. Approximate desiredten- 'sion'(grans) '50 3.Incoming tension 2 10 33 11 16 20 4. Inherent minimum ad dition 8 8 '88, 8 5. Tension desired'to be ad- L i ded by load=(2) v 3) 4 40 31. 6731 '26 '22 6. Load required for desired tension= (5)](1)-.. 66. 7 52. 851. 7 43. 3 36. 7 7. Total load available 1, 500 1,500 1,500 1,500 1,5008. Dead weight..- "50 '50 505 '50 50 9 1,450 1,450 1,450 -1, 450 1,45010. Load ed' by final tension (See 13 below) (13) M 1, 436.7 1, 4501,450. -1, 450 1, 450 11. Net load'appiied. 63.3 '50 50 50 '60 i2.Tension applied byl 1 I ing 37. 98 30 e 30 30 30 13. Fi'ial I l,

Table I shows that the device provides -a-'cornpensat1ng action forincoming tensions up to l2'-grams,-' whereas Table -Iashows that thedevice 1 provides -a compens atingaction for incoming tensions rangingonly up to 7 grams.

Such increase in coefficient also reduces the zone in which acompensating action is obtained in the device of Table II having thelarge mechanical advantage. Table II shows a compensating action up toincoming tensions of 5 15.33 grams, whereas Table IIa shows acompensating action for incoming tensions only up to 10.33 grams.

It may be seen from these Tables I, II, Ia and Ho that in the portion ofthe scale in which a compensating action is not produced, a change incoefficient from 0.5 to 0.6 increases the outgoing tension by 5 grams.Thus, close regulation is not consistently obtainable anywhere in thisregion, because various coeflicients will be encountered in practice.

Thus while the regulation has been improved in the .iower range ofincoming tension, by adopting the large mechanical advantage of 30rather than the relatively :small mechanical advantage of 10, acorresponding improvement is not shown throughout the scale.

It is therefore a problem how to extend the range of incoming tensionsfor which the benefits of a large mechanical advantage are secured.

The present invention takes into account the fact that in order to causea large mechanical advantage of the yarn arm to be effective to givegood regulation at both the higher and lower values of incoming tension,the effect of dead weight or unrelievable weight should be reduced. Anysubstantial reduction of the efiect of dead weight in Tables I to III,In and IIa would have been helpful since it would have extended upwardthe region in which a true compensating action would be obtained. Itwould also have reduced the eifects of variation in coefficient. Byreducing the dead weight sufiiciently, it is possible to avoid thecondition shown in several columns of Tables I, II, III, Ia and IIawhere the net load applied (item 11) .35 considerably exceeds the loadrequired (item 6) and a true compensation is not obtained. If the deadweight is completely counteracted the range of incoming tension forwhich true compensation is secured can extend up to the desired finaltension minus the inherent minimum addition, i.e. an incoming tension of42 g. for the device of Table II.

Table IV diliers from Table II by having its total load relievable, andhaving no dead weight.

Table IV [M =30. Dead weight =0] 1. Coe'ficient 0.5 2. Approximatedesiredtension (grams) 3. Incoming tension 2 10 15 16 20 4. Inherentminimum addition 8 8 8 8 8 5. Tension desired to be added by load=(2)(3) (4) 40 32 27 26 22 6. Load required for de sired tension= (SJ/(1)..-80 64 54 52 44 7. Total load available-.. 1,500 1,500 1,500 1,500 1,5008. Dead wei ht 0 0 0 0 0 0. Relievabie load 1, 500 1, 500 1, 500 1, 5001, 500 10. Load counterbalanced by final tension (See 13bel0W)=(l3)XM1,425 1,440 1,449.3 1,451.4 1,458.9 11. Net load applied 75 60 50. 748.6 41.1 12. Tension applied byloading 37. 5 30 25.35 24.3 20. 55 13.Final tension (3)+(4)+ It will be seen that, for incoming tensions up toand 65 tion persists for the higher incoming tensions of 16 and a 20grams.

For the range of incoming tensions from 2 grams to 20 grams, there is amaximum variation in final tension of only 1.13 grams.

The following Table IVa, assuming a coefiicient of 0.6 instead of 0.5for the device of Table IV, shows that L the device represented by TableIV is insensitive to V assesse a u variation in coeflicient. In Table Nofor the range of incoming tensions from 2 grams to 20 grams, there is amaximum variation in final tension of only 0.95 gram.

Table IVa [M=30. Dead weight=01 1. Coetficient 0.6 2. Approximatedesired tension (grams 50 3. Incoming tension 2 10 15 20 4. Inherentminimum ad ti n 8 8 8 8 5. Tension desired to be added by load=(2)-(ID-(4) 40 32 27 22 6. Load required for desired tension= (5)/ (1) 66. 753. 3 4 36. 7 7. Total load available 1,500 1, 500 1,500 1,500 8. Deadweight..- 0 0 0 0 9. Relievable load 1,500 1,500 1,500 1, 500 10. Loadcounterbalanced by final tension (See 13 below)=(l3) XM 1, 436.7 1,449.31,457.4 1,405.2 11. Net load applied 63.3 50.7 42. 6 34. 8 12. Tensionapplied by loading 37.98 30. 42 25. 56 20.88 13. Final tension (3)+(4)+It will be noticed that the total load of 1500 grams is equal to theapproximate desired tension of 50 g. multiplied by the mechanicaladvantage of 30 of the yarn arm. This total load is such as would betotally relieved when the incoming tension added to the inherent minimumaddition of 8 g. will equal 50 g., that is, when the incoming tension is42 grams. This is a higher incoming tension than may be encountered inmany cases. It may therefore be desirable to use a greater total load,such that the desired 50 grams final tension will be obtaine for somelower value of incoming tension.

The total available load appropriate to give a desired final tension forany particular incoming tension and inherent minimum addition may becalculated by ascertaining the load required for this desired tension(item 6 of Table IV) and adding to this load the product of the desiredtension and the mechanical advantage. It may be seen from Table IV thatto obtain a final tension of 50 g. when the incoming tension is 20grams, the total load available should be 1500 plus 44 grams.

Table V represents a device having a mechanical advantage of 30 and nodead weight and a total available load of 1544 grams. This table showshow the regulation, over a wide range of incoming tensions, is scarcelyaffected when the coefiicient changes from 0.5 to 0.6.

When the mechanical advantage is high, as in Table IV, the final tensionwill be sufiiciently close to the desired tension if the total loadavailable is simply made equal to the desired tension times themechanical advantage of the yarn arm, as in Table IV.

The reduction or elimination of dead weight becomes increasinglyimportant when the device, as in the preferred form of this invention,includes a considerable number of individual upper disks, interconnectedby linkage and all controlled by the yarn arm.

The reduction or elimination of dead weight is best effected byproviding the individual upper disks with individual springs adapted tosustain the weight of the upper disks, the plungers and the linkages andconnections whose weight the yarn arm is ineifective to relieve, so thatby means of the springs the yarn is relieved from the downward pressureoccasioned by the weight of the disks, plungers and linkage.

It is not essential that the weight of these parts be entirely sustainedby the springs, but it is desirable that the springs should be able tosustain this weight when and if the relievable weight is totallyrelieved by the action of the yarn arm.

The springs may be if desired even stiffer than would be necessary tosustain the weight of the dead weight parts, and no harm is done ifthese springs, in addition to sus- 1. Coefficient "0.5 2. Approximatedesired tension (grams) 50 50 "3. comingtenslo 2 10 20 2 4. Inherentminimum addit1on.'..' 8 8 8 8 5. Tension desired to be 'added "by'loa'd='(2)- j (3)(4) 40 '32 22 40 6. Load required fordesirod'tension=(5)/(1) 80 64 i 44 66.7 7- TOtal load available 1, 5441,544 1, 544 '1, 544 8. Dead weight... 0 0 9. Re1ievableload.-; 1, 5441,544 1,544 1,544 10. Load counterbalanced by final tension (See 13below) (13) XM- 1,466. 1 "l, 481. 1 1, 500 1,478. 4 5 11. Netloadappliedfn 77.9 62.9 44 65.6

12.Tenslon"a"pp1ied by'loading -1 38. 95 31. 45 50 39. 36 13. Finaltension (3)+(4)+ taining this weight, also tosome extent oppose andnullify the downward force of the 'reliev'able weight.

For instance in Tables IV and V, where it is assumed that the value qfdead weight has been eiractly eliminated,

by calanlation or by trial, opp osing forceof grams 0 would need to becompe hsated for, "and the total load favailablewould be ZOgramsgreater, in'or derto' apply the .sarne tensions. Eomin g"tensions,"asshown inYtli'ese I abl es Iv ;and V would thnyield the same'finaltensions as Shown niltsa bls i. r 4 r r -Althgugh see ingg gdreg istionover a wide'rang'eof incoming tensions very desirable, and requiresconsideration of t he problem of dead weight and use of a suilicientlylargei rne cha'riical advantage"M,'the matter of passageof knots mustalso be considered, v n The problem of: d o r unrelievableweighfaffecting the compensatingactlon is avoided in'the'type of tensiondeviceinwhich the pressure of the disks is regulated by yarn-controlledpositively 'actir g connections which bear against the lowerisurfaces ofthe disks "and force them upward against a loading force applied totheir upper surfaces; thus in the patent to I IeiZ'erNo. 2,629,561 eachof two upper disks'is forced upw-ardfr'orn'b'elow by connectionsfrom;thelyarrr' arnrfso that thefweight of the disks cannot beconsidpred unrelievable. That construction,.

however, in my opinion does notaccomplish the present inventions objectof offering the min i-mum resistance to dis-placement ofthe' disks byknots. That Construction involves making available a load, actingdownwardly on the tops of the disks, somewhat in excess of the force,

needed to bring the yarn from condition of zero tension or at leastrninimurn incoming tension up to the full tension at which it is desiredthe yarn shall leave the disks. Therefore, displacement of a disk by aknot is opposed by considerably more than the amount of force which thedisk applies to the yarn under average running conditions when thepotential load is considerably relieved. From the standpoint of avoidingbreak-age it would be much better if only the partially relieved loadupon a disk opposed itslifting to admit a knot. This partially relievedload, in the device of the present application will, on the average, bemuch'less than the maximum load which is applied. only when the incomingtension is zero.

It mightlbe though thatin the device of the Heizer patent only the netorpa'rtially relieved load upon the disk would oppose lifting of thedisk by a knot. However, further consideration willshow that the inertiaof the yarrr arm and 'connections to the lower face of the disk I. 1.tsvs t. thes a sf e' Tspondinglio. t s

egr eejthat-the disk mnst respondwithin the "iractionof a "second inwhich a knot is p'r'yin tha 'di sk upw'ardly. Thus" in the device of theHeizer patent, the actual prying apart of the'disks is necessarilyopposed by an increased load upon the upper disk, which increase will beconsiderable "in mostcases, representing increase up to the disks shai'e of the full potential load; g'reaterthan necessary for even acondition of zero incoming tension. In the device of the presentapplication itis sought to avoid thistype of increase'in' load'and tokeep the load, at'the moment-of prying apart of the'disks, substantiallyno greater than the partially relieved value/which thedevice has beenmai The accomplishment of this involves use of the; yarn arm torelieve-aweightwhich is used as a loadyand pro- 'vision of a system oflinkage to distribute the unrelieved portion of the loadto aconsiderable number of movable "disks.

The tension device of this invention is shown "as mounted on ahorizontal plate or platform 21 having a vertical flange 21 the plate orplatform 21 being-adapted to be a part of the head of an automaticwinding unit, not shown. 7

Yarn Y enters the device through a suitable yarn guide or pigtail 23mounted'on the plate 21'and leaves the device through a guide or pigtail24 carried at the end of a yarn arm 25, passing thence downwardly to thewinding unit. Ann 25 is aflixed to a sleeve 26 which pivots freely onthe reduced end portion of a shaft 2.7 rotatable in a bushing 28 inflange 21a, Fig. 5.

It is desired to make the passage of knots very easy, and to this end aconsiderable number of easily lifted upper disks 30 are employed,preferably siX as shown.

Each disk is rotatable about a'central plunger 31which isverticallyslidable in a sleeve 32 fast in theplate 21.

The several disks 30 are preferably located in an arc and the yarn Y isdirected by the pigtail 23 and by small vertical guide posts 34 and bythe pigtail 24 in courses which traverse the successive disks as chordsof the disks circular perimeters, each at about one-half of the radiusof the disk from its center. Underlying the course of the yarn beneatheach disk a yarn supporting platform 35 of polished'rnetal providesa'srnooth path for the yarn in contact with the disk. Opposite to theyarn supporting platform 35, each disk is supported by a pin or button36, also of smooth polished metal, supported from the plate 21. Theundersurface of the rotatable disk, beipg "largely: "exposed; in'th'esense of being largelybutf bf cohtacit with'any other part, the rotationof the disk readily jsw'eiepsdust or fly off fromthe yarn supportingplatform,

., et f rce pr p v e a hewak e t I linkage "comprises" an initiallinkj'40fiFig'. 4, 10 which.

d is applied "at"; s (center: rhed twosecondary links 4rand'42- onto eac0 which games the initial link 4i) is hooked, and spring wires 43, 44

and 45. Spriiig wires 43 and 45 pass through holes in upturned ends ofthe respective secondary links 41 and 42. Spring wire 44 extends throughsimilar holes in the adjacent upturned ends of both links 41 and 42. Theend portions of spring wires 43, 44 and 45 pass through holes in theplungers 31 and can apply downward force thereto. Thus there is anindividually springy connection, comprising one end portion of a springwire 43, 44 or 45 between each plunger and the remainder of the linkage.The points of engagement of the initial link 40 with the secondary links41 and 42 are such that each plunger 31 is equally loaded.

The individually springy connections with the plungers of the diskspermit the disks to be lifted easily and quickly by passing knotswithout having to overcome the inertia of the initial and secondarylinks or of the rather massive adjustable weight employed in the device,the means for transmitting force from this weight to link 40, and othermovable parts such as the yarn arm.

The means for applying net force to link 40 includes a lever 50 which isheld fast to the shaft 27 by a locking nut 51, Fig. 5.

A weight 52 is held by a hook 53 in any one of several holes in thelever so as to provide an adjustable amount of torque force at the shaft27.

Shaft 27 carries a lever 55, Fig. 2, which bears against an adjustingscrew 56 in a lever 57 fast on a shaft 58 which rotates in arms 60extending from the under sur- :face of plate 21. Shaft 58 has an offsetcrank portion 58a which bears in a valley or pocket in the middle of theinitial link 40 to apply a downward force thereto. By adjusting theposition, or if desired the size, of weight 52 a potential force(corresponding to the relievable load previously referred to) ofadjustable amount can be provided at crank 58a and the middle of theinitial link 40. In running, a large part of this potential force isrelieved and offset by the action of the yarn arm 25 so that only thenecessary net force is applied to initial link 40 for distribution tothe several movable disks.

It should be noted that this potential force will usually be so largethat when this potential force is not largely relieved the springs 43,44 and 45 would be considerably distorted. However, when the yarn arm 25is not acting to relieve this potential force, the weight arm 50 dropsuntil it encounters a stop bracket 61, Fig. 3, whereupon the springs 43,44 and 45 are no further distorted. It will be understood that thesesprings are light in order to permit easy lifting of the individualdisks by passing knots.

The relief of potential force by the action of the yarn arm isaccomplished by the yarn arm 25 bearing downwardly upon a bent forwardend portion 50a of the weight arm 50. It will be seen from the length ofthe yarn arm 25 and the effective lengths of levers 55 and 57 and crank58:: that the mechanical advantage of the yarn arm (at its pigtail 24)with reference to the point of application of force by the crank 58a islarge, being in the construction shown 38.85. Therefore whether the loadis determined by calculation and the weight 52 adjusted to provide thisload at the crank 58a and middle of link 40 or the weight 52 is simplyadjusted according to experience to yield the desired outgoing tension,the device will give a close compensation by virtue of the highmechanical advantage.

To obtain this colse and consistent compensation for the relativelyhigher values of incoming tension (that is, relatively high with respectto the desired outgoing tension) the dead weight which is unrelievableby the yarn should be reduced or eliminated. In the device of thisapplication, this problem of dead weight is increased over any problemof dead weight in any ordinary tension device because of the presence ofthe system of distributing linkage of which the weight cannot berelieved by the yarn and, as well as by the presence of the considerable number of plungers and disks.

In the device as shown in Fig. 6 a light compression spring 65 isinterposed between each upper disk 30'and screw 56 without pressure uponthe yarn on the yarn supporting platforms 35, thereby eliminating thefactor of dead weight. As indicated above, no difficulty is encounteredif the springs 65 are a little stiffer than re quired for merelyrelieving the dead weight, in which case a slightly greater load shouldbe made available at the crank 58:: and middle of initial link 40. Thesprings 65 are not interfered with by the yarn, or vice versa, becausethe guide pins 34 hold the yarn well away from the springs. The sectionline 7-7 in Fig. 6 passes.

through the line of travel of the yarn.

There are certain advantages in employing flat springs: instead of thecoil springs 65. Figs. 8 and 9 show a. construction in which the yarn issupported by a lower' disk 66 which is loosely centered about the sleeve32 by' a locating washer 67 of dished shape. A generally flat: spring 70is supported at its ends by the washer 67 and v is loosely centered bythe sleeve 32. A little tubular element 71, also loose on the sleeve3.2, is interposed between the lower surface of upper disk 30 and thespring 70. The effect of this construction is to sustain the weight ofthe parts that would otherwise have a dead weight effect. In Fig. 8 thespring 70 is shown as slightly deflected by its share of the weight ofthese parts.

The system of linkage and associated parts of the tension device areparticularly intended to avoid back,- lash or lost motion such as wouldcause loss of control of the tension or cause hunting. First, it will beapparent from the drawings that the effect of the weight of the variousparts of the linkage is always such as to stress the elements of thelinkage in a manner tending to apply downward force to the disks. Also,it may be seen that whatever force is applied to the linkage undercontrol of the yarn arm is also such as to stress the elements of thelinkage in a manner tending to apply downward force to the disks. Forexample, the lever 55, Fig. 2, is never called upon to force lever 57upwardly and crank 58a is never called on to force link 40 upwardly, andin fact lever and crank 58a can only exert downward force. Thus thelinkage may be said to be free of reversals of stress during operation,and this feature eliminates backlash and lost motion. The springs ornevertheless prevent the weight of the linkage parts from constitutingan uncontrolled or unrelievable dead weight load upon the disks.

The movement of the weight arm 50 damped by a dashpot indicated at 80.

It may be noted that in the construction shown the weight arm 50,without any weight 52, would exert some torque on the shaft 27 and henceprovide some load at the crank 58a. It may in some cases be desirable tomore or less balance the movable parts (minus the weight 52) around theaxis of shaft 27, so that the torque effect is preferably of the weightof the parts other than the weight 52 is eliminated or reduced and amore nearly direct relation secured between the position of the weight52 and the load made available. For this purpose there may be provided acounterbalancing weight 52a adjustably positioned on the weight arm 50.

By way of example, it may be assumed that the weight or weights areadjusted, either by means of calculation or by trial and error, so thata load of 2006.5 grams is available at the middle of initial link 40.The figure of 2006.5 grams may he arrived at by multiplying the desiredtension 50 grams) by the mechanical advantage (38.85), making a productof 1942.5 grams, and adding to this latter the item of 64 grams. Thisadjustment corresponds knots without breakage.

rsess enrich*withaa imsommgeasier!"erinsists The final tensionofapprokimately so'igr'amsgaetmg leaving only approximately "64 gramsnet" or llnrelieved load, to be divided among'thesiX disks'and appliedthere- "to by the springy' connections.

n will 'be uridrstood that the aboveadju'stmentand condition ofoperatidn"arereferred to only by wa fof *explanation' of the invention,and that these maybevaried widely. V

'Also, no attempt is" made to set forth theactriakweights of parts ofthis device which wouldcontr'ibiite tothedead "weight (were'this de'adWeight not counteractedby the springs 65- m7 0) because the" weights ofthese'parts will naturally vary with their sizes, "which in 'turn' 'willvary with the specific design'ofthe device.

I claim: I

1. An automatietension device cor'npri'singa plurality of tension disks,means for supportingthe' yarn against to the several disks-loadingmeans- "for"applying saidforce "to the linkage, a yarn ar'rn 'ur'ge'd'by the tension of the running yarnto relieve the force of theloading-"means "applied to the linkage; the device including aconnectio'n between the yarn" arm and the loading mans for pre-*mit'tingthe yarn arm to relievesaid'for'ce, wherebyme 'n'et loadcomprised of the force' afiorded 'by 'theleading' means as relieved bythe force afiorded'by the 'ya'r-n arm is distributed' to the severaldisks, said linkage-* ineluding individually springy connections to theindividual disks, each said springy connection-to a disk'receiving itsdistributive share of said net load and being yieldable to permit itscorresponding disk to lift to admit'a knot.

2. An-automatic'tension' device comprising 'afplurality of tensiondisks, meansfor supporting the yarn against said'disksya linkagesuspended from the several disks,

"said linkage having a-point'at which downward forceis applied theretoand distributing said force from sa'id point to the several disks, aweight connected'to the linkage to" exert the said force upon thelinkage, a"yarn"arm urged by the tension of the running yarn to'relievethe force of said weight applied to the linkage, the device/ including aconnection between the yarn arm and the weight for permitting theyarn'arm to relieve'said'fo'rce, whereby the netload comprised of theforceafi'orded by the-'wei'ght as relieved'by the force affordedbythelyarn ar m- 'is distributed to the'several disks, saidlinkage'including individually springy-connectionsto theindividual'disks,

each said 'spr'ingy connection to a disk receiving its distributiveshare of said net load and being yieldable' to permititscorrespondingdiskto lift to admit alarm.

p 3. AEa'HtOinatIc" sionde'vice comprising aph'irality :"of*ter'isionidis'k's, ans "fdfsuppo'rting the yarn' "against *said disks,'plu' s for "pulling the disks "down "against the "supporting nsfalinkage -suspended "from the "several plli'n'ge'rs, said linkage'havingaipo'int atwhich idownwardior'ceis"applied theretoand distributing said'fo'rcetro'rn said point to the several'plungers, a'weightconnected"tothe' linkage to exert the saidforce'on the 'linkage,a yarnarm urged b'ythe tension'of the running yarn' to 'relievethe' force ofsaid "weight "applied to the linkage, the device including a connectionbetweenthe yarn arm and" the weightfor permitting'thelyarn arm torelieve said force, wherebythe'net load comprised of"theforceafford'ed'by theweight as relieved by the force *a'fiordedbytheyarn'arrn is distributed to the several,

disks, said linkage including an' initial yoke receiving said net load,secondary yokes each'receiving a share of saidnet load from the'initialyoke, and springy'connec- 'tions from" the secondaryyokes to theplungers,-each said springy connection to a'plunger'receiving itsdistributive share of said net loadandbeing 'yieldable'to permit itscorresponding 'disc to lift" to admit a knot.

4. An automatic tension device comprising av plurality oftension-disks;meansfor supporting the yarn against said disks,plungers'adapted to pull the respective disks downwardly, s'prin'gy wireconnections between pairs of said plungers, 'a system' of linkagesuspended from the spring'y 'wire connections, said linkage having apoint at which uownwar'd force is" applied thereto and distributing saidforce froni 's'aid point to the springy-wire connections,-awei'ght"connected toapply downward force to the linka'ge at "saidpoint; a yarn arm responsive to the tension of the "yarn'and-connectedtothe'weight so as to relieve the aewnwardrorce 'applidby'the weight thusvarying the netdownward' force appliedto the linkage, wherebyeach saidspringy connect'ion receives its distributive share of said net downwardforce, so-that the springy connection to any-individuakplunger permitseasy lifting of the corresponding upper" disk bya passing'knot.

5. A yarn tensiondevice comprising a plurality of upper disks, "supportsfor the yarnbeneath said disks, plungers for pulling the upper disksdown against the running yarn'on-the supports, a system of linkageinterconnecting'said plungers, loading means for applying a downwardforce tosaid linkage,the linkage distributing said force tothe'plungers,a yarn arm responsiveto the yarn'ten'sion and c'onnectedto said loadingmeans for relieving 'said forcef-said linkage including individualspringy connections to the'several plungers, such springy connectionseach receiving its distributive share of'the net downward force appliedto the linkage as a whole, and individual springs associated with theindividual upper disks and tending to relieve the yarn fromdownwardpr'e'ssu're occasioned by weight of the disks, plungers andlinkage 'wh'en'said yarn arm relieves said "downward force.

" References" Cited in'the file of this patent UNITED STATES PATENTSPigeon has. Nov. 14, 1922

